Chapter 24: Platelet, blood coagulation and haemostasis Flashcards
What is the major regulator of platelet formation?
Thrombopoietin
Which organ produces Thrombopoietin?
Liver
True or False? TPO levels are high in patients with Thrombocytopenia but LOW in patients with a raised platelet count.
TRUE!!
True or False? After TPO therapy, platelet count should rise 8 days after.
FALSE!! It should rise 6 days after.
What is the lifespan of platelets?
10 days
What is the measurements of a single platelet?
3.0 × 0.5 μm in diameter
What is the main function of the glycoproteins found on the of the surface coat of platelet?
They are particularly important in the platelet reactions of adhesion and aggregation.
Fill in the blanks. “ _____________ is defective in Bernard–Soulier syndrome.”
Glycoprotein Ib
What is the function of Glycoprotein Ib?
It is important in the initial attachment of platelets to von Willebrand factor (VWF) and hence to vascular sub-
endothelium.
Which platelet glycoproteins facilitate adhesion to exposed collagen of the vessel wall?
Glycoprotein Ia- IIa and VI
What is another name for Glycoprotein IIb/IIIa ?
Integrin αIIb and β3
A defect of Glycoprotein IIb/ IIIa is defective in which disease?
Glanzman’s thrombasthenia
What is the main function of Glycoprotein IIb/IIIa?
It is important for additional binding of platelets to VWF and for facilitating platelet–platelet aggregation, both by binding to VWF and to fibrinogen, which is also involved in platelet– platelet aggregation.
Where are platelets produced?
Platelets are produced in the bone marrow by fragmentation of the cytoplasm of megakaryocytes.
Fill in the blanks. “ Megakaryocytes mature by __________.”
Endomitotic synchronous replication ( i.e. DNA replication in the absence of nuclear or cytoplasmic division)
